How reliable are witnesses really

Why do we remember wrongly

Scientists speak of change blindness here: Because we can only remember a very limited amount of information, we focus our attention on one point and ignore events around it.

That is why we often do not notice that our partner was at the hairdresser's, that is why magic tricks work and that is why important details can be missing in observations by witnesses.

It's hard for us to remember new faces

Even if we do not notice it in everyday life: We have great difficulty in reliably memorizing new faces. Even with new colleagues and acquaintances, many of us find it difficult to immediately recognize them in a different environment, with different clothes or a new hairstyle.

Identifying people from a photo is also very difficult for us. In a study, test subjects were shown a man whom they were to find again shortly afterwards in a series of photos. 40 percent of the participants failed. A week later, those who recognized the man were supposed to filter him out of a series of photos again. Only 65 percent of them could remember correctly.

In order to remember faces, we associate them with faces we already know. In the memory, these faces can then mix and ultimately you do not know for sure whether the man who had a nose like our friend also had similar eyes or completely different ones.

It is easiest for us to recognize people who are similar in age and appearance. We find it difficult to recognize people who are much younger or older. It is very difficult to recognize people of other ethnicities: to a white man, all Asians look more or less the same - and vice versa. Being different is a problem for memory.

We like to reconcile our memories

We are constantly sharing other people's experiences and perspectives through social media such as Facebook or Twitter. It sometimes happens that the countless information and images overshadow our own experience.

Shaw calls this process "memory conformity", an alignment of experiences: It is then no longer clear what you have experienced yourself, what others have transmitted and what actually happened at all.

Descriptions of different people about the same event are therefore often surprisingly identical - not only in social networks.

A continuation of this is "memory borrowing", the borrowed memory: You take on other people's memories as your own - perhaps because you want to upgrade yourself or want to belong to it or because you don't trust your own memory.

The acquisition of false memories through photos works in a similar way: If test subjects are presented with many vacation photos with well-known landmarks several times, after a while some claim to have already visited these places themselves. Some even remember their own experiences - for example an elephant ride that never took place.

Witnesses don't necessarily tell the truth

Eyewitnesses cannot be trusted either. Witnesses who do not tell the truth are usually not liars. You remember wrongly, have not noticed essential facts or have come to a wrong picture of the situation through influencing third parties. Sometimes because they trust others to make a better assessment than they do themselves, sometimes because they have thought through a situation so often that their personal assessment no longer corresponds to what actually happened.

It is therefore important for police work to avoid any kind of suggestive questioning or personal assessment during interrogations, to keep witnesses separate from one another so that they do not provide themselves with false information and, above all, to always be aware that there are false memories.